1. Technical Field
The present invention relates to a carrier for manufacturing a substrate and a method of manufacturing a substrate using the same.
2. Description of the Related Art
Generally, printed circuit boards (PCBs) are manufactured by patterning one or both sides of a substrate, composed of various thermosetting resins, using copper foil, and disposing and fixing ICs or electronic parts on the substrate to form an electric circuit and then coating the substrate with an insulator.
Recently, with the advancement of the electronics industry, electronic parts are increasingly required to be highly functionalized, light, thin, short and small. Thus, printed circuit boards loaded with such electronic parts are also required to be highly densified and thin.
In particular, in order to keep up with the thinning of printed circuit boards, a coreless substrate which can decrease thickness by removing a core and can shorten signal processing time is attracting considerable attention. However, a coreless substrate needs a carrier serving as a support during a process because it does not have a core. Hereinafter, a conventional method of manufacturing a coreless substrate will be described with reference to FIGS. 1A to 1E.
FIGS. 1A to 1E are sectional views sequentially showing a conventional method of manufacturing a substrate using a carrier, and FIG. 2 is an enlarged view showing an essential part of a first metal layer and a second metal layer shown in FIG. 1. Problems of conventional technologies will be described with reference to FIGS. 1A to 1E.
First, as shown in FIG. 1A, a carrier 10 is provided. The carrier 10 is fabricated by sequentially forming adhesive films 12, first metal layers 13 and second metal layers 14 on both sides of a copper clad laminate (CCL) 11. In this case, the carrier is heated and pressed by a press, and thus the copper clad laminate 11 and the second metal layer 14 attach to each other at a periphery thereof by means of the adhesive film 12. Meanwhile, in order to stably attach the copper clad laminate 11 and the second metal layer 14 to each other, the contact face therebetween must have a thickness of 10 mm, and the first metal layer 13 and the second metal layer 14 are vacuum-adsorbed.
Subsequently, as shown in FIG. 1B, build up layers 15 are formed on both sides of the carrier 10. Here, each of the build up layers 15 is formed in a general manner, and is additionally provided with a third metal layer 16 for preventing the warpage of the build up layer 15 at the outermost layer thereof.
Subsequently, as shown in FIG. 1C, the build up layers 15 are separated from the carrier 10. Here, the build up layers 15 are separated from the carrier 10 by removing the edge of the adhesive film through which the copper clad laminate 11 and the second metal layer 14 are attached to each other by a routing process.
Subsequently, as shown in FIG. 1D, the second metal layer 14 and the third metal layer 16 formed at the outermost layers of the build up layer 15 are removed by etching.
Subsequently, as shown in FIG. 1E, openings 17 for exposing pads 19 are formed in the outermost insulation layers of the build up layer 15, and then solder balls 18 are formed on the pads 19.
In the above-mentioned conventional method of manufacturing a substrate, copper foil is used as the first metal layer 13 and the second metal foil 14. However, the copper foil includes a matte surface (M surface) having high surface roughness and a shiny surface (S surface) having low surface roughness. Therefore, as shown in FIG. 2, small space (S) is formed between the first metal layer 13 and the second metal layer 14 due to the matte surface (M surface), and thus it is difficult to completely maintain a vacuum. Consequently, there is a problem in that wrinkles occur when the build up layer 15 is formed on the second metal layer 14.
Further, even when pin-holes are formed in the first metal layer 13 or the second metal layer 14, there is a problem in that a vacuum is not maintained between the first metal layer 13 and the second metal layer 14, and thus it is difficult to continue a process.
Furthermore, when the build up layers 15 are separated from the carrier 10 by removing the edge of the adhesive film 12 through a routing process, the build up layers 15 warp in an extreme manner due to the difference in material properties between the second metal layer 13 and the insulating material of the carrier 10. Therefore, there are problems in that process automation cannot be realized and in that subsequent processes must be manually performed.